Abstract 14250: Differential Left Atrial Posterior Wall Remodeling With Proximity to the Thoracic Descending Aorta
Background: Atrial fibrillation (AF) is associated with structural left atrial (LA) remodeling. The extent of late gadolinium enhancement (LGE) on cardiac MRI is associated with AF recurrence following ablation. In our experience, we have noticed LA posterior wall enhancement adjacent to the aorta that seems unrelated to extent of atrial disease.
Hypothesis: Due to its pulsatile nature, the aorta is implicated in fibrotic remodeling of proximate LA. We examined here the association between aortic proximity and distensibility with the extent of adjacent LA LGE.
Methods: One hundred and nine patients presenting for an index AF ablation underwent pre-procedural MRI. The descending thoracic aorta and LA myocardium were manually segmented (Figure). The extent of LGE was quantified using the normalized image intensity ratio as percent mass of LA wall. The average distance between the aorta and the atrial wall was quantified using a custom-written software and aortic distensibility (Δarea/areamax) was measured from cine-MR.
Results: Overall 15.2±10.8% of the LA exhibited LGE. The extent of LGE was higher in the posterior LA (26.0±13.4% vs 8.0±6.3% in the anterior LA). Mean aortic distensibility was 11.4±5.3% and mean aorta-to-LA wall distance was 31.1±5.1mm. Aortic distensibility was directly associated with posterior LA LGE (p=0.009) after adjusting for age, CHA2DS2-VASc score, AF type, total atrial LGE burden and LA volume in multivariable linear regression. The average distance between the LA myocardium and aorta was inversely related to posterior myocardial LGE extent (p<0.001). As a control, there was no association between aortic parameters and anterior LA LGE.
Conclusion: The extent of posterior LA LGE is higher in AF patients with greater aortic distensibility and shorter distance between the descending aorta and LA. Our findings support a potential direct remodeling effect from aortic distension upon the posterior LA.
Author Disclosures: T. Zghaib: None. S. Zahid: None. E.G. Ipek: None. J. Chrispin: None. B.A. Venkatesh: None. D. Huang: None. M.A. Balouch: None. S. Misra: None. J.E. Marine: None. D.D. Spragg: None. R.D. Berger: None. S.L. Zimmerman: None. N. Trayanova: None. H. Calkins: None. J.A. Lima: None. S. Nazarian: None.
- © 2016 by American Heart Association, Inc.